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Fused Filament Fabrication of Metal-Ceramic High-Density Polyethylene Composites
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- Author / Creator
- Bhardwaj, Nancy
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This thesis focuses on the manufacturing of high carbide content wear-resistant parts by extrusion- based Additive Manufacturing (AM) based on the principles of Powder Metallurgy (PM). A new manufacturing technique, termed Fused Filament Fabrication of Cermets (FFFC) is presented. First, particle packing theory is applied to develop a methodology for maximizing packing density and carbide content in non-ideal binary powder mixtures. Based on this optimization, sinterable metal-ceramic polymer filaments suitable for Fused Filament Fabrication (FFF) are prepared and printed. It is shown that a traditional polymer 3D printer can be used to successfully deposit high- density polyethylene (HDPE) composite filaments containing up to 46 vol% Ni-TiC and Ni-WC fillers, to produce dense green parts for sintering. A characterization of the composite filaments and resultant printed parts is provided. An analysis of the random loose void fractions in dry fillers and the fraction of polymer in the composite after polymer is injected into the dry filler is presented. It is concluded that, the maximum void contraction (∆Θmax) is a function of the ratio of mean particles sizes (δ) in binary dry powder mixtures. As δ decreases and the particle sizes become more dissimilar, an increasing deviation from the ideal rule-of-mixtures law is observed. The critical δ is revealed to be 0.65. Furthermore, when dry filler is mixed with HDPE to form composite filaments for FFF, the particles are rearranged, and the polymer content of the filled composite is greater than the void fraction observed in dry filler packing. Fillers having lower dry void fractions, reported higher polymer contents in their composites. The important role of non- ideal particle packing in binary filler mixtures is emphasized, where the goal is to produce high carbide content cermet parts. Some remarks about process parameters that influence part quality and suggestions for future work are included.
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- Subjects / Keywords
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- Graduation date
- Spring 2022
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.